Sources: Disturbances Of The Heart
This condition of auricular fibrillation occurs occasionally in
valvular disease, and perhaps most frequently in mitral stenosis;
but it can occur without valvular lesions, and with any valvular
lesion. If it occurs in younger patients, valvular disease is apt to
be a cause; if in older patients, sclerosis or myocardial
degeneration is generally present.
It may also follow infections such as diphtheria, or some infection
which has caused a myocarditis. Rarely this fibrillation may be
caused by some of the drugs used to stimulate the heart.
It is astonishing how few symptoms may be present with auricular
fibrillation and an absolutely irregular heart action. The patient
may be able to perform all of his duties, however strenuous, until
coincident, concomitant or causative ventricular weakening and
dilatation of the ventricles or broken compensation occurs, and then
the symptoms are those due to the cardiac failure. Often in the
first stage of this weakening and later fibrillation of the auricles
the patient may recognize the cardiac irregularity and disturbances.
Generally, however, he soon becomes accustomed to the sensations,
and, unless he has cardiac pains or dyspnea, he becomes oblivious to
the irregularity. At other times he may be conscious of irregular,
strong throbs or pulsations of the heart, as such hearts often give
an occasional extra sturdy ventricular contraction. These he notes.
Real attacks of tachycardia may be superimposed on the condition.
Sooner or later, however, if the condition is not stopped, cardiac
weakness and decompensation, with all the usual symptoms, occur. It
seems to be probable that more than half of all cases of heart
failure are due to auricular fibrillation, or at least are
aggravated by it.
As previously stated, ventricular fibrillation is a very serious
condition, and may be a cause of sudden death in angina pectoris,
and is probably then caused by disturbed circulation in one of the
coronary arteries causing an irregular blood supply to one or other
of the ventricles. Absorption of some toxins or poisons which could
act on the blood supply of the ventricles could also be a cause of
this condition. This irregular ventricular contraction sometimes
displaces the apex beat.